CPM S90V vs M390
The wear-resistance extreme against the balanced benchmark. S90V out-cuts M390 on raw edge retention — that is its entire design — while M390 answers with better toughness, friendlier sharpening, easier sourcing and lower cost. The right pick depends on whether the knife is a dedicated slicer or has to be good at being a knife.
Quick Verdict
S90V for the dedicated slicer whose owner has diamond stones and wants maximum cutting endurance; M390 for everything else premium - it does 85% of S90V's cutting with meaningfully better toughness, sharpening and availability. When in doubt, M390 is the saner knife.
Toughness
M390, clearly. Neither is tough by general standards, but S90V's 9% vanadium carbide volume puts it at the bottom of the stainless chart - thin edges chip on staples M390 survives. Both want sensible angles; S90V demands them.
Edge Retention
S90V, decisively - this is the one column it was designed to win, and CATRA-class testing puts it clearly above M390/20CV. In abrasive media (cardboard, rope) the difference is obvious in use, not just on charts.
Corrosion Resistance
Close, M390 by a nose - 20% chromium versus 14% leaves M390 a little more margin in wet service. Both are honestly stainless for EDC and kitchen life; neither is a salt-water steel.
Heat Treat
Same discipline, different sheets: high-temp soak, plate quench, cold treat, low temper - kiln territory for both. S90V typically lands 59-61, M390 60-62. Neither forgives skipped cold treatment; neither is forgeable.
Grinding
M390 is hard work; S90V is a commitment. Nine percent vanadium defeats conventional abrasives outright - ceramic belts for shaping, diamond/CBN mandatory for sharpening, roughly double the shop time of M390. Factor the labor into the price of every S90V blade.
Best-Use Scenarios
S90V: cardboard-and-rope working slicers, hunting blades for diamond-stone owners, spec-sheet flagship folders. M390: premium EDC generalists, kitchen knives, any customer who says ‘low maintenance’ – and any maker quoting realistic build hours.